Air cushion cargo handling system



Oct. 3, 1961 1-. K. PETERSEN ETAL 25,045

AIR CUSHION CARGO HANDLING SYSTEM Original Filed June 11, 1958 2 Sheets-Sheet 1 INVENTOR? Arraeve/ Unit dSW8|Pa h 1QT1i 25,045 AIR CUSHIONzCARGO HANDLING SYSTEM Thorvald K. Petersen and Paul L. Smith, Santa Monica, Calif., assignors to Douglas Aircraft Company, Inc., Santa Monica, Calif.

Original No. 2,918,183, dated Dec. 22, 1959, Ser. No. 741,399, June 11, 1958. Application for reissue Sept. 21, 1960, Ser. No. 58,589

12 Claims. (Cl. 214-1) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

This invention relates to article-handling, as in loading cargo into a conveyance or in shifting and stowing articles on a floor.

Most of the effort expended in moving such articles under such circumstances is the result of overcoming the frictional drag or resistance exerted between the bottom face of the article and the supporting floor. The conventional pallet ameliorates this situation somewhat but vided for achieving this end despite such irregularities in the floor as would otherwise reduce the contact of the cargo-unit with the floor to a series of ridges, lines or points which would not only allow the lubricant film to escape but would be likely to cause jamming, binding or the like of the cargo-unit on the floor. One form of means for accomplishing this result resides in a novel resiliently yielding lowermost floor group or laminate on the pallet or, in a special case, on the bottom of the container itself. In either 'case, this laminate comprises a substantially rigid floor-sheet constituting the bottom of the container, at lowermost layer of smooth flexible, "conformable material, such as a smooth slick plywood or linoleum, and an intermediate layer of a foamed plastic, such as a foamed rubber, polyurethane, or the like. The maximum load per square foot is restricted to that which will not exceed the limit of compressibility of the foamed plastic and deaerate it. In some cases,

sponge type material is satisfactory. However, in shifting the cargo-unit over tessellated or ribbed cement floors, some escape of air is unavoidable at one or two loci of the unit, but due to the conventionally wide spacing of these cracks, and. to the automatic conforming of the novel lower surface of the new cargo unit to shallow depressions or concavities in the carrying floor, the remainder of the unit will be properly engaged and aided in its translation by the remaining lubricating air' layer. Further means are also provided at each end-edge of the cargo-unit'that, like the upturned toe of a ski, rides over minor obstructions in the path of the cargo unit.

Solely in order to render the inventive concepts more concrete as well as to detail the mode and'principle of embodiment thereof, several ones of the now-contemplated embodiments of the invention are illustrated, by

way of example only, in the accompanying drawings and will be described hereinafter in conjunction with these drawings.

In these drawings,

FIG. 1 is a perspective view of the rear end of a con- Re. 25,045 Reissued Get, tip-1 5 2 a veyanee provided with a construction according to the present invention by means of which articles supported according to the invention are being stowed therein with the 31d of a more or less conventional loading ramp, skid, or the like;

FIG. 2 is a fragmentary longitudinal section of a species of the improved floor of the conveyance and of a portion of the improved pallet and load carried thereby;

FIG. 3 is a similar view of another species of the'inventton that includes a'variant floor and pallet; and

' FIGURE 4 'is a fragmentary perspective view of a reusable contaiuer capable of use directly withthe type of transport floor shown in FIGURE 1 without theintermediancy of a pallet.

The present concepts are, for illustrative purposes, shown in FIGURE'I as embodied in the stowageof cargo-units in a conveyance such as a cargo airplanes fuselage, a van, or other vehicle. i

The vehicle 12 includes a species of floor ;13 which, at equidistant intervals both longitudinally and laterally thereof, includes a plurality of controlled air-inlet ports each provided with air-flow controlling means 14. Means 14 are supplied with low-pressure air, and are interconnected bya manifolding system illustrated in FIGURE 2 at 27. The cargo-units 15 here comprisea container or containers 16 lashed down to novel pallets 17 by such tie-down tensile units as those at 18.

In the orthodox manner, a loading ramp, skid," or tail gate 19 supplied with the usual forwarding rollers 20, is

'or ball-obturator 24. The ball is spring urged to a normally closed position by a compression spring 25 and each lower perforation communicates with the pressure air manifold system 27. Each ball protrudes above the floor level a distance such that when the ball is urged downwardly into flush relation to the floor, the valve is opened.

As shown in FIGURE 2 the novel pallet, while having the usual rigid wood or metal uppermost surface 32 otherwise differs materially from the conventional pallet. For one reason, the lowermost face group, 32A which is spaced from the uppermost by trusswork 33, as shown, comprises a laminated structure. This structure includes a rigid wooden or metal layer 28, a lowermost layer 29 which is of special smooth, flexible nature such as that provided by thin plywood or linoleum and is adapted to yieldingly conform to rugosities in the floor of the vehicle; and an intermediate layer 30 of some such resiliently-compressible material as foamed rubber, foamed polyurethane, or the like. Be it what it may, this layer 30 is to compress, not so much bydensification of its own ,materi'al as by compression, of the air trapped in the pockets of the foamed material, for reasons later becoming apparent. Further, the unit-load on it is precalibrated for this .3 together they constitute in efiect a single very rigid layer to take the direct burden of the loads placed on the pallet.

The pall cl de a m t ll fl m v 4 qm s na w o, and on the palletthe nature .of a The periphery .of the pallet is, as shown at 35, upwardly, in the manner of a ski's portion, thereby to enable the pallet to overrride minor obstructions during the movement of the cargo-unit.

A further species of the invention is shown in FIG- 3. One of the therein over theone previously is that the pressurized air is supplied entirely to the pallet itself and is distributed between the pallet and the carrying floor by meansofopen 3 I8 -s p 32A of pallet from the trusswork space 38 that separates the rigid upper surface 32 from the bottom-laminate. An aimurr y ws rliss r isra l o? the s msim type, entrants the air into space 38.

In 4 the can caus em n r w box 40 is so constructed as toobviate the necessity for a separate pallet'initsuse with the floor of FIGURE 1, yet is nonetheless capable of performing substantially all the functions of the aforedescribed species. To these, other, ends, it comprises, in addition to the usual .rectapgular side-framing .and fla t p, a laminated bottom or floor 42 integral with-the remainder of the box) The lamina 46' consists of a rather thick, rigid wooden flooring, the lowermost 44 consists of a sheet of the same,or equivalent, smooth flexible material aforedescribed, such .as linoleum, as and for the purpose described, and theintermediate l aminaconsists of the sort of resiliently yieldable material, such as foamed polyurethane orfoarned rubber, or sponge rubber as is .hercinabove In use, the species of FIGURES 1 and 2 is urged readily along the cargo floor with flexible lamina 29 contacting a plurality of the ball-valves, urging them downwardly sufliciently (1) to clear the floor of their protuberant condition and (2) to release air underneath thetravelling container that, in a sense serves as a lubricant layer for the whole bot-tom area of the pallet,

in that it quite materially reduces the moving coeflicient of friction, from about 0500 down to.0.00l. Themanual eflort required to load or place the cargo is obviously thereby considerably reduced, as is theelapsed time for stowage. The air layer is not relied upon primarily for lift, or sustentation .of the containers so as to reduce their gravitational efle'ct or weight, but does play some part in facilitating their movement. The linoleum, or other, flexible layer is cushioned resiliently by the foamed: material, which functions by virtue of the of the trapped air in the foam-pockets, .thus rendering it even more resilientthan the rubber or .polyurethane itself. 'Ihebottommost layer 29 is abrasion resistant as well as flexible and the entire lower group of the pallet can conform to, and case out of, slight depresisons in the vans floor. The latter, incidentally, is to be, planar, rigid and as free of irregularities as is feasible for the expense involved in so rendering it. lf'the device is moved over cement floors having expansion joints or cracks therein, some air may escape laterally, but the remaining air-layer will be adequate for present purposes. 'The plywood or linoleum layer can dip into slight but "broad depressions and conform thereto, wherealiter it regain its original shape.

The species ofFIGURB 3 performs substantially the same functions as thatof FIGURE 2, withthe'possible that "there are no :chances of ball-valves iammingtin their-protruding original positions and obstructing the passage of the. cargomnit.

The species of FIGURE 4 incorporates .the advantage reusability: plus-:eradication of pallets.

The air pressure can varyfromabout-l p.s.i.- to. 5;.p.s.i. parametersand; specific terminology 4 have been hereinabove employed, such constitutes no limitations on the scope ofthe invention per se, which scope is defined in the sub-joined claims.

We claim:

1. Cargo handling apparatus comprising: a main support adapted to'lrave'cargo placed thereon; a lower lamina of sheet-like generally planar flexible material aflixed to said main support and being adapted to directly contact a surface across which the cargo is to be moved; an intermediate lamina of vrnul ticellul ar material rendered resiliently compressible and dimensionally-recuperative by air trapped in the cells, said material lying immediately adjacent said lower laminate and being interposed between said main support and lower lamina, said intermediate lamina being adapted to locally expand and be compressed upon 'flexure of the lower lamina when the latter contacts local irregularities in said surface whereby the lower lamina will have substantiallyfull contact with said surface; and multi outlet means supplying a flowof a pressurized gaseous medium between the lower lamina and slufacqsaid multi outlet means being oriented to effect the of a him how of the gaseous fluid across substantially the entire area of the lower lamina whereby the coeflicient of friction between the lower lamina and the surfaceis substantially reduced and the lateral force required to move the cargo is proportionately reduced.

.2. Cargobandling apparatus comprising: a rnain support ad apted to, have cargo placed thereon; alower of sheetrl-ike generally planar flexible material affixed to said main support and being adapted to directly contact and slide upon a generally planar across which the cargo to bemoved; an intermediate lamina ofresiliently compressiblematerial immediately adjacent said lower laminate and being interposed between said main supportand, lower lamina, said intermediate lamina being adaptedto locally expand and be compressed upon flexure of the lower lamina when the latter contacts local irregularities in said surface whereby the lower lamina will have substantially full contact with said surface; a plurality of outlets in said apparatusand extend-ingthrough :the intermediate and lower laminae and supplying a flow of a pressurized gaseousmedium between the lower lamina and the surface, said multi outlet means being oriented to effect the distribu-tionof a flow of thegaseous fluid across substantially theentire area of the lower lamina whereby the coeflicient of friction between the lower lamina andthe surface is sumbstantially reduced and the lateral forcereqnired to move thecargo is proportionately reduced.

3. Cargo :handling apparatus comprising: a main support adapted to have cargo placed thereon; a lower of sheet-like generally planar-flexible material-allixed to said main support, at least a portion of the periphery of said lamina .being curved upward y; an intermediate lamina of resiliently compressible material immediately adjacent said lower lamina and being interposedbetween :said main support and lowerlaminma floor-like structure having a,generally planar-surface across the main support is moved with the lower lamina in face toface contact with said sm'facesaidintermediate lamina being adapted to locally expand and be compressed upon flexnre of the lower lamina when the latter contacts local irregularities insaid surface; aplurality of outlets spaced generally uniformlyin the. of said floor-lilre structure; a sourceofpr .gas. communicating with said outlets; .valve means normally closing .said outlets; and operatingmeans for said valves, .S 096 m 1 means protruding above thesurface of the floor-like ture and beingdepressible bysaid lower lamina whereby to ofthe valves and. a distribution of the pre s ri sa b we n h su fac n the lower 4. Cargo handling apparatus comprising: a port adapted to have cargo placed thereon; :alower lsminaicfsahe telik rzcw llyrplanar flexible ma r-chaffixed to said main support and being adapted to directly contact a surface across which the cargo is to be moved; an intermediate lamina of resiliently compressible material immediately'adjacent said lower lamina and being interposed between said main support and lower lamina, said intermediate lamina being adapted to locally expand and be compressed upon flexure of the lower lamina when the latter contacts local irregularities in said surface whereby the lower lamina will have substantially full contact with said surface; multi outlet means supplying a flow of a pressurized gaseous medium between the lower lamina and the surface, said multi outlet means being in and at the lower lamina and being oriented to eflect the presence of a film flow of the gaseous fluid across substantially the entire area of the lower lamina whereby the coeflicient of friction between the lower lamina and the surface is substantially reduced and the lateral force required to move the cargo is proportionately reduced; and a gaseous fluid distribution system in said apparatus connected to each of said multi outlet means; and a quick detachable connection to said distribution system for cornmunicating with a source of gaseous fluid.

5. Cargo handling apparatus adapted to be moved across a floor-like structure on a film of constantly flowing pressurized gaseous medium, comprising: a laminated construction including an upper main support of rigid material adapted to substantially inflexibly support cargo thereupon, a lower lamina of a tough, abrasion resistant, flexible, generally planar, sheet-like material adapted for gliding contact with the surface of the floor-like structure, said lamina by its flexibility being adapted to conform to minor irregularities in said surface to'thereby have subctantially full face to face contact therewith at all times, and an intermediate stratum of aerosol material in which the major portion of the compression is taken by the air in the aerosol, said stratum lying between the upper main support and the lower lamina and transmitting the load of the cargo therebetween, said stratum being only partially compressed by a nominal maximum load of cargo whereby there is under normal load conditions residual compressibility to accommodate inward distortions of the lower lamina in passing over convexities in thesurface of the floor-like structure.

6. Cargo handling apparatus adapted to be moved across a floor-like structure on a film of constantly flowing pressurized gaseous medium, comprising: a laminated construction including an upper main support of rigid material adapted to substantially inflexibly support cargo thereupon, a lower lamina of a tough, abrasion resistant, flexible, generally planar, sheet-like material adapted for sliding contact with the surface of the floor-like structure, said lamina by its flexibility being adapted to conform to minor irregularities in said surface to thereby have substantially full face to face contact therewith at all times, and an intermediate stratum of multicellular, foamed, plastic material, said material undergoing compression substantially solely in the air entrapped in its cells, said stratum lying between the upper main support and the lower lamina and transmitting the load of the cargo therebctween, the solid-phase portion of said stratum being only partially compressed by a nominal maximum load of cargo whereby there is under normal load conditions residual compressibility to accommodate inward distortions of the lower lamina in passing over convexities in the surface of the floor-like structure; a plurality of gaseous fluid outlets terminating immediately adjacent the lower lamina at its under surface, said outlets being uniformly spaced whereby when pressurized gas flows through the outlets a moving film of fluid is ejected across substantially the entire lower surface of the lower lamina; and means connecting said outlets with a source of pressurized gaseous fluid.

7. Load handling apparatus adapted to be moved across a floor-like structure on a film of constantly flowing pressurized gaseous medium, comprising: a load, and

interposed between the load and the floor-like structure, a stratum of multicellular foamed plastic material in which the main compressive load is taken by the air in the foamed plastic, there being at least one pressurized gaseous fluid outlet terminating in communication with the lower surface of said stratum, whereby under normal loads there is residual compressibility in said stratum to accommodate distortions of said stratum in passing over rugosities in the surface of the floor-like structure and whereby when pressurized gas flows through said outlet a moving film of fluid is ejected across the entire lower surface of said stratum.

8. Cargo handling apparatus comprising: a mam support adapted to have a load placed thereon; a lower lamina of sheet-like generally planar flexible material affixed to said main support and being adapted to directly contact a surface across which the, cargo is to be moved; an intermediate lamina of mullicellular material being resiliently compressible and dimensionally-recuperative, saidvmaterial lying immediately adjacent said lower luminate and being interposed between said main support and lower lamina, said intermediate lamina being adapted to locally expand and be compressed upon flexure of the lower lamina whemthe latter contacts local irregularities in said surface whereby the lower lamina will have substantially full contact with said surface; and outlet means supplying a flow of a pressurized gaseous medium between the lower lamina and the surface, said outlet means being oriented to efiect the presence of a film flow of the gaseous fluid across substantially the entire area of the lower lamina whereby the coefficient of friction between the lower lamina and the surface is substantially reduced and the lateral force required to move the load is proportionately reduced.

9. Cargo handling apparatus comprising: a main support adapted to have a load placed thereon; a lower lamina of sheet-like generally planar flexible material affixed to said main support and being adapted to directly contact and slide upon a generally planar surface across which the load is to be moved; an intermediate lamina of resiliently compressible material immediately adjacent said lower lamina and being interposed between said main support and lower lamina, said intermediate lamina being adapted to locally expand and be compressed upon flexure of the lower lamina when the latter contacts local irregularities in said surface whereby the lower lamina will have substantially full contact with said surface; at least one outlet in said apparatus and extending through the intermediate and lower laminae and supplying a flow of pressurized gaseous medium between the lower lamina and the surface, said outlet being oriented to effect the distribution of a flow of the gaseous fluid a'cross substantially the entire area of the lower lamina whereby the coefficient of friction between the lower lamina and the surface is substantially reduced and the lateral force required to move the load is proportionately reduced.

10. Cargo handling apparatus comprising: a' main support adapted to have cargo placed thereon; a lower lamina of sheet-like generally planar flexible material affixed to said main support and being adapted to directly contact a surface across which the cargo is to be moved; an intermediate lamina of resiliently compressible material immediately adjacent said lower lamina and being interposed between said main support and lower lamina, said intermediate lamina being adapted to locally expand and be compressed upon flexure of the lower lamina when the latter contacts local irregularities in said surface whereby the lower lamina will maintain substantially full contact with said surface; outlet means supplying a fl w of a pressurized gaseous medium between the lower lamina and the surface, said outlet means being in and at the lower lamina and being oriented to eflect the presence of a film flow of the gaseous fluid across substantially the entire area of the lower lamina whereby the coeflicient of friction between the lower lamina and the surface is mbstantially reduc d n th la era te se. required t ma e the cargo is proportionately reducedta gaseous fluid duct means in sai pp atus con ected to said outle means; and a quick detachable connection to said fluid duct means for communication with a source ,of gaseous fluid.

I1. Cargo handling apparatus adapted to be moved across a floor-like structure on a film of constantly flowing pressurized gaseous medium, comprising! a construction including an upper main support of rigid material adapted to substantially inflexibly support cargo thereupon, a lower lamina of a tough, .abrasifl resistant,

flexible, generally planar, sheet-like mqlelial adapted for gliding contact with the surface of the flaor-lilte sttructure, said lamina by its flexibility being adapted to conform ,to minor irregularities in said surface to-thereby have Substantially full face to face contact therewith at all times, and an intermediate stratum of aerosol material in which ,the major portion of the compression taken 'by the air in theaerosol, said stratum lying between the upper-main support and the lower lamina and transmittittgthe load of the cargo therebetween, said stratum being anly partially compressed by a normal maximum loadofjcargo whereby ,there is under normal load conditians-residuallcompressibility to accommodate inward distortions of the :lower lamina in passing over convexities in the surface ofthe floor-like structure; a sourceof pressurized 8 qtldfoutlet means emitting the gas inwardly of .the periphery of the :laminated construction and between .the lower and the floor-like structure.

12. Cargo handling apparatus adapted to :be moved construction including an upper main support rigid .material adapted to substantially inflexibly support cargo thereupon, a lower lamina of a-toughiabrasion resistant,

flexi le. sheet-l ke materia hav n a e e a Pl na m surface adapted for sliding contacfwith the surface of the floor like structure, said lamina by its flexibility being adapted to conform to minor irregularitiesin said surface to thereby have substantially full face to face contact therewith at all times, and an intermediate stratum of multicellular, foamed, plastic material, said plastic material undergoing compressio'n substantially solely in the air entrapped in its cells, said stratum lying between .the upper main support and the lower lamina and transmitting the load of the cargo therebetween, the solid-phase portion of said stratum being only partially compressed by a nominal maximum load of cargo whereby there is under normal load conditions residual compressibility to accommodate inward distortions of the lower lamina in passing over convexities in the surface of the .fl or like structure; gaseous fluid outlet means terminating immediately ady'acent the lower lamina at its under surface, said outlet means being Spaced inwardly from the periphery of the lower lamina whereby when pressurized gas flows through the outletmeans a moving film of fluid is ejected across substantially the entire lower surface of the lower lamina;

and means connecting said outlet means with a source of pressurized gaseous fluid.

References Cited the tile of this 'ot'the original patent UNITED STATES PATENTS patent Great Bsitain Apr. 17, 1957 

